Those present were nervous that Dorner might do something rash when he learned that he was being stripped of his badge. He was a hulking, muscled man and his body language left no doubt about the anger seething out of him.

"It was clear… that he was wound way too tight," said a police official who attended Dorner's termination hearing and requested anonymity because of safety concerns.

That day four years ago, authorities now allege, was the start of a free fall into despair and deadly violence for Dorner. Police say the 33-year-old ex-cop killed three people and injured others on a campaign to exact revenge against those he blamed for his downfall.

Friends and acquaintances who knew Dorner before he became a police officer struggled to reconcile the person they remembered with the image of the deeply disturbed man that emerged Thursday from a rambling manifesto that authorities said was published on what they believe is Dorner's Facebook page. The manifesto portrays Dorner as having no choice but to kill in order to reclaim his destroyed reputation.

"I am a man who has lost complete faith in the system, when the system betrayed, slandered and libeled me," the manifesto states.

Born in New York state, Dorner grew up in Southern California with his mother and at least one sister, according to public records and claims in the manifesto.

Dorner felt isolated growing up as one of the few African American children in the neighborhoods where he lived and was the victim of racism, according to the manifesto. "My first recollection of racism was in the first grade," Dorner allegedly wrote, recalling a fellow student at Norwalk Christian School who called him a racial slur. Dorner said he responded "fast and hard," punching and kicking the student.

It was an early, telling illustration of a notion Dorner returned to repeatedly throughout his life — that he was a victim, often wronged by others, records show.

As a teenager in La Palma, Dorner joined the Police Department's youth program, and decided to pursue a career in law enforcement.

Dorner went on to enroll at Southern Utah University, where he joined the school's football team and was befriended by a teammate, Jamie Usera.

Usera, who grew up in Alaska, said he and Dorner bonded over the feelings of culture shock that came with being outsiders on the predominantly white, Mormon campus.

Usera said he introduced Dorner to hunting and other outdoor sports. "He was a typical guy," he said. "I liked him an awful lot. Nothing about him struck me as violent or irrational in any way. He was opinionated, but always seemed level-headed."

Dorner often brought up race issues and the two had heated, but respectful arguments about the extent of racism in the country, Usera said. "Of all the people I hung out with in college, he is the last guy I would have expected to be in this kind of situation."

Neil Gardner, an assistant athletic director, knew Dorner through football and echoed Usera, saying Dorner was "never a disgruntled guy."

Dorner graduated in 2001 with a degree in political science and, soon after, enlisted in the Navy. Over the next several years, military records indicate Dorner received extensive combat and counter-terrorism training and earned commendations for his marksmanship with rifles and pistols.

In 2005, while still enlisted in the military, Dorner applied to the LAPD and earned a spot in one of the department's training academy classes. An officer in Dorner's class who asked not to be identified because he is not authorized to discuss the case, recalled Dorner as "one of our problem children" who frequently pushed the bounds of authority .

A few days into training, the recruits were explicitly told to only wear white or black shoes for a conditioning run, the officer said. Dorner, however, showed up in bright neon sneakers. "He thought he knew it all, that rules just kind of didn't apply to him," the officer said. "He was not a team player."

According to the officer, Dorner was kicked out of his academy class at least one time, when he accidentally shot himself in the hand. Internal disciplinary records show that Dorner was suspended for two days for an accidental discharge in 2005. He finished his training with another academy class, the officer said, and joined the force as an officer in February 2006, police records show.

Months later, the Navy called him back into service and he departed for a 13-month deployment in Bahrain. When Dorner returned to the LAPD in July 2007, he had not yet completed his mandatory probation year and was partnered with Teresa Evans, a training officer in the San Pedro area.

Evans would later tell internal affairs investigators that Dorner confessed to her on the first day they worked together that he was unhappy with the way the LAPD handled a complaint he made against some of his classmates in the academy, according to police records. He believed the LAPD was a racist organization and told Evans he planned to sue the department at the end of his probation period, Evans reported.

Dorner repeatedly made mistakes in the field, Evans said. Shortly after becoming partners, they responded to a report of an armed man and Dorner stood in the middle of the street to confront the suspect without any cover, she said. Evans said she told Dorner that she was going to recommend that he be removed from the field unless he improved his performance, according to the internal affairs records.

Dorner, she said, repeatedly asked to return to the academy for more training after his return from military service and was upset that the department had not granted the request. On one occasion, Dorner cried in the patrol car with Evans and demanded the additional training, she said.

The struggling officer's ultimate undoing began on the morning of July 28, when he and Evans were dispatched to a report of a man who had refused to leave a local hotel.

The officers found the mentally ill man seated on a bench. When he refused a command to stand up, Dorner took the man's wrist and pulled him up, records show. A struggle ensued and Evans had to grab Dorner's Taser stun gun from his belt to subdue the man.

Nearly two weeks later, Evans criticized Dorner harshly in an evaluation report that included a long list of areas in which he needed improvement, including using common sense and good judgment. About the same time, Dorner called an LAPD sergeant whom he knew from the Navy and claimed he had witnessed Evans kick the man while he was being handcuffed. The sergeant told Dorner to report the incident to higher-ups or said he would do so himself. Dorner reported the misconduct, records show.

The department's internal affairs unit launched a probe into Dorner's allegations. Three hotel employees who witnessed much of the incident said they never saw Evans kick the man. And when the man arrived at the police station, he did not mention being kicked in the face when a physician treated him for his facial injuries. Investigators concluded there was no truth to Dorner's claim.

The witnesses' statements and Dorner's delay in coming forward "irreparably destroy Dorner's credibility," the department concluded in disciplinary records. Dorner was charged with making false statements and a false personnel complaint.

At Dorner's discipline hearing, the father of the man the partners arrested testified that his son had told him he had been kicked by an officer. Nonetheless the discipline board, found that Dorner had lied about the incident and fired him.

Dorner spent the next couple of years unsuccessfully appealing his termination. Then, this week, police say, Dorner made good on his threat to seek revenge when he fatally shot the daughter of an ex-LAPD captain who represented him at his discipline hearing. He also allegedly shot her fiance. Dorner went on to fatally shoot one officer and injure two others, police say.